''I remember when these women had little fashion from which to choose,'' says Evelyn Roaman, a pioneer in special sizing. ''Stores with extensive stocks in other departments were content to show a woman who wore a half-size just two or three dresses. And if she wore a larger size, the attitude was 'forget it.' The fashions they did have either didn't fit properly or looked dowdy.''

Mrs. Roaman is now vice-president and fashion director of Roaman's, the nation's largest retailer devoted exclusively to large and half-size women's apparel. (The company's discount chain is called Sizes Unlimited.)

''I believe then, and I still do, that fit is the most important asset. No dress can look right if it's tight where it should fall close to the body,'' says Mrs. Roaman, a size 14, who entered the family business in 1943 when her husband, David, went into the service.

''Half-size and larger-size women can wear any fashion, provided it's adapted for them,'' she says. ''It's all a matter of scaling -- shaping a design with subtle changes to flatter the woman with ample proportions.''

With the market growing, many stores have departments for special sizes. At the Women's World section of Filene's in Boston, prices vary from $62 for a purple tent dress by Chez California to $74 for an Amy Adams khaki tent. Both are perfect transitional dresses from now into fall.

One well-dressed customer who wears a size 201/2 says, ''I only buy tent dresses, and then I accessorize them with necklaces. Sometimes I wear gold chains and other times I like big, wooden beads. I get lots of compliments on this look.''

Another attractive larger-size woman says, ''I happen to like separates, but I choose them carefully -- usually in quiet colors with no frills. Mixing separates is an art. It can be messed up if it isn't done with thought.''

If you're a home sewer, there's still more good news. The pattern houses couldn't be more in step with the fashions being shown in the stores. And they have patterns in every size imaginable. For example, under ''Special Measures,'' Simplicity has patterns for half-sizes, women, and large miss.

''The pattern business is exploding in the large sizes. We have more space in our catalog than ever before, and we're increasing,'' says Beth Keillor, director of marketing and fashion publicity at Simplicity.

Ms. Keillor offered some tips to the half-size and large-size women:

* Think enough of yourself to invest in fine fabrics and sophisticated designs for career clothing.

* Experiment with color, not just the neutrals.

* Experiment with such features as pleats or stripes.

* Look for designs with shoulder interest such as gathers, ruffles, and shoulder pads. (This will balance the bottom-heavy figure and attract the eye to the face.)

* Wear fashions with movement at the hemline. (This is flattering to the legs and detracts from the hip area.)

* Wear undergarments that fit properly.

For women who work, pattern No. 5245 shows a model wearing an unlined red plaid jacket with matching lined vest and black skirt. The pattern, available in half-sizes, also includes straight-leg pants.

Butterick and Vogue Pattern Company also offer variety to the special-size woman.